The present invention relates to a transmission and/or conveyance chain of the type with lubricant sealed by ring seals.
Transmission and/or conveyance chains having pins on which are bushes sealed at the ends by O-rings compressed between the plates of the chain to retain grease or lubricating fluid are known. Chains of this type are used for example in the motorcycle field.
One of the problems of the above mentioned type of chain is the life of the seal rings which when they begin to wear allow lubricant to come out of the joints. Lubrication thus becomes insufficient and the joints wear rapidly to make the chain unserviceable.
Another problem with prior art chains is that during assembly the known seals tend to be xe2x80x9cpinchedxe2x80x9d between bushes and plates of the chain. Shaped seals also tend to be reversed or get stuck during assembly.
The general purpose of the present invention is to remedy the above mentioned shortcomings by making available an innovative chain of the type with a supply of lubricant which thanks to an innovative shape of the seals allows recovery of play and keeps hydraulic seal of the lubricant for a long time.
In view of this purpose it was sought to provide in accordance with the present invention a chain with link pairs made up of outer and inner plates connected respectively by pins and bushes fitted on the pins and projecting through the inner plates with there being between the bush and its pin a lubricated interface and on each end of the bush there being mounted and compressed between an inner and an outer plate an annular seal characterized in that the seal when not compressed between the plates is generically shaped with a lip projecting towards the axis of the seal with said lip tending with the chain assembled to wedge between the bush and the outer plate in such a manner as to recover the wear on the seal.